I haven't been inside of an 8.25 in awhile, but the bolt your talking about is fairly universal. They are hard but they are brittle, I've never seen anybody have much luck trying to drill one (maybe a diamond drill will work?). Depending on where it broke off, near the head or down deeper there are a few approaches I've used with success. If the break is right near where the head used to be, Dremel a slot in the bolt and try a screw driver (after the head is gone most of the pressure on the threads should be gone). If it is broken down deep, you can try a punch and drive it into the pin, it will screw up some of the threads but the top threads will still be OK if you are careful with the punch.
Once I actually drilled a quarter inch through the side of the spider gear carrier, exposed about half the threads on the bolt and then punched it through.
I'm not sure if the 8.25 is the same as the D35, but at least on the last D35 I checked, the hole for the bolt goes all the way through the pin and also through the ring gear carrier.
As far as putting it back together after you have the bolt stub out, I've been lucky and after re taping, had enough good threads to hold a replacement bolt. Or I used a steel pin in place of the bolt and spot welded the ends of the cross pin as insurance.
The next time whack the top of the bolt head with hammer before you start and be careful with that sucker. I remove them with feeling, tap it with a hammer wiggle a little, tap it agian wiggle a little. I've never snapped one off, but have helped remove more bolt stubs than I care to remember.
If I remember correctly Chrysler used some sort of Loc Tite on there cross pin bolts. And the Loc Tite they used was a little too stiff for the application, that was back in the 80's it's likely a non issue now. There is a solvent for Loc Tite available, it may be hard to find, acetone may work.